首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   293篇
  免费   0篇
电工技术   4篇
化学工业   38篇
金属工艺   5篇
机械仪表   1篇
建筑科学   8篇
能源动力   12篇
轻工业   29篇
无线电   57篇
一般工业技术   24篇
冶金工业   98篇
自动化技术   17篇
  2023年   1篇
  2022年   3篇
  2021年   6篇
  2019年   2篇
  2018年   3篇
  2017年   2篇
  2016年   4篇
  2014年   3篇
  2013年   9篇
  2012年   7篇
  2011年   13篇
  2010年   9篇
  2009年   11篇
  2008年   3篇
  2007年   7篇
  2006年   6篇
  2005年   10篇
  2004年   12篇
  2003年   6篇
  2002年   5篇
  2001年   2篇
  2000年   3篇
  1999年   9篇
  1998年   36篇
  1997年   24篇
  1996年   10篇
  1995年   8篇
  1994年   11篇
  1993年   10篇
  1992年   4篇
  1991年   6篇
  1990年   7篇
  1989年   2篇
  1988年   3篇
  1987年   2篇
  1986年   1篇
  1985年   5篇
  1984年   3篇
  1983年   5篇
  1982年   5篇
  1980年   3篇
  1979年   1篇
  1978年   1篇
  1977年   2篇
  1976年   4篇
  1975年   1篇
  1974年   1篇
  1971年   1篇
  1966年   1篇
排序方式: 共有293条查询结果,搜索用时 15 毫秒
101.
102.
We previously demonstrated the presence and fragmentation of mitochondria during alcohol fermentation. Here, we show that Fis1p induces mitochondrial fragmentation, and inhibition of mitochondrial fragmentation causes higher malate production during sake brewing. These findings indicate that mitochondrial morphology affects the metabolism of constituents, providing a breeding strategy for high-malate-producing yeasts.  相似文献   
103.
104.
Development of an implantable motor-driven assist pump system   总被引:1,自引:0,他引:1  
A motor-driven artificial pump and its transcutaneous energy transmission (TET) system have been developed. The artificial pump consists of a high-speed dc brushless motor driving a ball screw and magnetic coupling mechanism between the blood pump and ball screw. The ball screw transfers high-speed rotary motion into low-speed rectilinear motion by a single component. Magnetic coupling enables active blood filling without applying an excess negative pressure to the pump. The transcutaneous transformer is formed from a pair of concave/convex ferrite cores. This design minimizes lateral motion of the external core. Information on motor voltage is transmitted through the skin by infrared pulses. The motor voltage is regulated by controlling the duty ratio of the square pulse supplied to the primary coil. Pump flow of 5.6 l/min was obtained with a mean outlet pressure of 100 mmHg at a drive rate of 100 bpm under preload of 15 mmHg. The performance of synchronous pumping has been very satisfactory. Continuous pumping was maintained by the backup battery in the case of interruption of TET. 24 W were transmitted by TET system with 78 percent of efficiency. Temperature rise of the internal core was 0.2 C. The developed system is promising as an implantable assist pump system.  相似文献   
105.
A case of agenesis of the left internal carotid artery with an aneurysm of the anterior communicating artery was reported in detail. The patient was a 48-year-old man who had an episode of subarachnoid hemorrhage about 10 years ago. This time left heminumbness and motor weakness of the left lower extremity occured and he was brought our hospital. Right common carotid angiography, left retrograde brachial serial angiography and aortography demonstrated an agenesis of the left internal carotid artery, an aneurysm of the anterior communicating artery, tortuous megadolic hobasilar artery and anomalies on the circle of Willis such as absence of supra optic portion of the right anterior cerebral artery, and large left posterior communicating artery. We confirmed latter findings by operation. After successful neck clipping of the aneurysm, his clinical findings were remarkably improved.  相似文献   
106.
Nasal reconstruction presents a significant challenge to the facial plastic surgeon. Reestablishment of the desired aesthetic nasal contour and restoration of respiratory function are the dual goals of this endeavor. While autologous cartilage or bone is considered optimal grafting material, the supply is often limited and harvesting entails additional morbidity. Many synthetic materials have been introduced for use in nasal reconstruction, but high infection and extrusion rates have left most surgeons dissatisfied with conventional implants. Porous polyethylene (Medpor) implants were used for nasal reconstruction in 187 patients; 66 (35.3%) patients underwent primary rhinoplasty, while revision surgery was performed in 121 (64.7%) patients. Most patients required multiple implants, including columella struts, plumper grafts, dorsal tip implants, and nasal valve battens. Postoperative follow-up ranged from 6 months to 3.5 years. Complications occurred in five (2.6%) patients. Three early and two delayed infections necessitated implant removal in five patients, all of whom had compromised skin-soft tissue envelopes secondary to heavy smoking, cocaine abuse, or prior surgery. One case of an overly augmented nasal dorsum and tip required implant removal, reduction, and reinsertion. All implants were easily removed. No other complications including implant extrusion or skin erosion have been noted. Porous polyethylene (Medpor) implants allow for fibrovascular ingrowth, which lends stability to the implant. Porous polyethylene implants are well tolerated and provide an ideal material for nasal reconstruction.  相似文献   
107.
An infra-red lamp-annealing technique was employed for postannealing Si ion-implanted InP substrates. The effective electron mobility (?eff) of SiO2-InP metal-insulator-semiconductor field-effect transistors fabricated using infrared lamp annealing is remarkably temperature-dependent. The maximum ?eff is ? 11000 cm2/Vs at 75 K and 1500?2500 cm2/Vs at room temperature.  相似文献   
108.
We characterized the nature and reaction mode of the cell growth-inhibitory factor (here designated CGIF) from rat peritoneal exudate cells (PEC). The soluble fraction separated from the lysate of Enterococcus faecalis-induced 24 hr PEC completely inhibited Con A-induced thymocyte mitogenesis. Gel filtration chromatography showed that CGIF has a molecular weight of approximately 23-25 kDa. Isoelectric focusing with Rotofor indicates that the factor has an isoelectronic point of 5.8-6.4. CGIF was inactivated by treatment at 70 C, for 30 min or by tryptic digestion, but the activity was not destroyed by the reduction with dithiothreitol. As well as thymocyte proliferation, CGIF completely suppressed 3H-thymidine incorporation of splenocytes which were stimulated by either Con A or LPS, suggesting the factor is effective on both T and B cells. The acting point of the inhibitor appeared to be a later stage of the lymphocyte activation sequence, since it was still effective when added 28.5 hr after the addition of Con A. CGIF also reduced the viability of these cells when added with mitogens such as Con A or LPS. CGIF thus appears to be distinct from interleukin-1 receptor antagonist or transforming growth factor-beta.  相似文献   
109.
This study examined the effects of long-term treatments with the angiotensin-converting enzyme inhibitor, enalapril, and the calcium antagonist, amlodipine, on the morphologic changes, progressive left ventricular dysfunction, and gene expression of the ryanodine receptor (RyR) and phospholamban (PLN) in dilated cardiomyopathy. From the ages of 5 through 20 weeks, dilated cardiomyopathic hamsters, BIO53.58 (BIO), and control hamsters, F1b, orally received either enalapril or amlodipine. Cardiac function was assessed by echocardiography. At the age of 20 weeks, the collagen volume fractions were analyzed by the stereologic method. RyR and PLN messenger RNAs (mRNAs) were examined by Northern blot in the amlodipine group. In BIO, the reduction of left ventricular percentage of fractional shortening was attenuated in the enalapril group (p < 0.05) and amlodipine group (p < 0.001), and the increase in the collagen volume fraction and the loss of myocytes were suppressed in the amlodipine group compared with the untreated group. RyR mRNA level decreased in BIO (p < 0.01) compared with F1b, but PLN mRNA level was unchanged. RyR and PLN mRNA levels were unaffected by the treatment with amlodipine. Enalapril and amlodipine prevent progressive remodeling and reduce cardiac dysfunction in BIO. Amlodipine prevents fibrosis and cell death without modifying RyR and PLN mRNA levels in BIO.  相似文献   
110.
Chick embryo fibroblasts (CEFs) infected with three strains of Marek's disease virus serotype 1 (MDV1), GA, Md5 and JM, were subjected to indirect immunofluorescence assay with monoclonal antibodies (MAbs) against MDV1 homolog of glycoprotein D (MDV1 gD) of herpes simplex virus. By the MAbs, a number of MDV1 gD-positive cells were detected in CEFs infected with GA, whereas only a few and no positive cells were detected in CEFs infected with Md5 and JM, respectively. The MDV1 gD in GA-infected CEFs was recognized as the band of 64 kDa in immunoblot analysis using one of the MAbs. This is the first report that the MDV1 gD was detected in MDV1-infected cell cultures.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号